Approximately 20-40% of patients with epilepsy have refractory seizures unresponsive to pharmacotherapy. Thus, there is a need to develop alternative treatments for this large population of people who are at higher risk of developing epilepsy-related disabilities.
Halorhodopsin is a membrane bound light-gated ion pump. Upon exposure to light, halorhodopsin moves chloride ions into a cell. Light induced halorhodopsin silences excitable neuronal cells. Zhao et al. reported the halorhodopsin from halophilic bacterium Natronobacterium pharaonis (NpHR) for light-induced silencing of neuronal activity. Brain Cell Biol, 2008, 36(1-4): 141-154. See also Zhang et al., Multimodal fast optical interrogation of neural circuitry. Nature, 2007, 446:633-639.
Luciferases produce light in the presence of luciferin. Coelenterazine (CTZ) is a substrate luciferin of Renilla reniformis luciferase (Rluc) and Gaussia luciferase (Gluc). Berglund et al. report using a luciferase for light-activating a channelrhodopsin for combined optogenetic and chemical-genetic control of neurons. PLoS ONE, 2013, 8(3): e59759. See also WO 2011/005978 and WO 2010/011404.
References cited herein are not an admission of prior art.